WATER 2

Open Ended

Explain how water acquires hardness as it flows through soil.

Multiple Choice

Why is the hardness of water considered significant in daily life?

• It affects the taste of water

• It influences the ability of water to form lather with soap

• It determines the color of water

• It changes the boiling point of water

Open Ended

Explain how temporary hardness of water is caused, mentioning the chemical compounds involved.

Multiple Select

Which of the following methods can be used to remove temporary hardness of water?

• Boiling

• Adding slaked lime

• Filtration

• Both a and b

Open Ended

Describe the difference between stalagmites and stalactites as related to temporary hardness of water.

Fill in the Blank

The insoluble calcium trioxocarbonate (IV) found in the inner surface of kettles is called ___.

Multiple Choice

Permanent hardness of water is caused by the presence of which ions?

• Tetraoxosulphate (VI) ions

• Chloride of calcium and magnesium ions

• Hydrogen trioxocarbonate (IV) ions

• Both a and b

Multiple Choice

Which method is used to remove both permanent and temporary hardness from water?

• Addition of washing soda

• Addition of caustic soda

• Ion exchange resin

• Distillation

Fill in the Blank

Hard water requires lots of soaps to form ___ .

Open Ended

Discuss the importance of chlorination and the addition of iodine and fluorine in the municipal water treatment process.

Multiple Choice

Which process in municipal water treatment involves adding chemicals like potash alum or sodium aluminate III to water in a large settling tank?

• Sedimentation

• Filtration

• Coagulation

• Chlorination